Family: Meliaceae

Origin, Description & Uses:
Toona ciliata (Australian red cedar) is native to southern China through tropical Asia and into eastern Australia. It is a fast-growing, deciduous to semi-deciduous hardwood tree in the mahogany family, valued globally for its high-quality timber. In Hawaiʻi, it has been extensively planted in forestry and windbreak plantings due to its rapid growth and useful wood, which has been used for furniture, cabinetry, veneer, and general construction. The species can establish in a range of mesic to wet environments, particularly in disturbed sites between approximately 25–610 m elevation. It was first recorded on Oʻahu as early as 1929, though it may have been introduced into cultivation even earlier, prior to 1871, and is now reported as naturalized across Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi Island.

Risks & Threats:
Although still valued for forestry plantings, Toona ciliata is now naturalized in Hawaiʻi and has traits that are cause for concern in tropical island ecosystems, including rapid growth, effective seed dispersal, and the ability to establish in disturbed mesic to wet forests. These characteristics increase its potential to spread beyond plantings and compete with native vegetation, particularly in lower-elevation and disturbed habitats where it can form self-sustaining populations. As a widely planted forestry species that has already become established across multiple islands, it should be carefully managed to limit further spread, especially in areas where it is not yet dominant. When possible, choosing low-risk or native alternatives is recommended, and continued use should be minimized in sensitive watersheds and restoration areas to reduce additional ecological impacts.

High Risk Traits:

• Naturalized outside native range
  
• Naturalized in Hawaii: Present on all main islands (Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi)
  
• Environmental weed in South Africa and Zambia (displaces natives in forests, gaps, riverbanks)
  
• Agricultural/forestry weed (invades plantations; classified as "remove and destroy" in South Africa)
  
• Broad climate tolerance (0–1500 m elevation; 750–4000 mm rainfall)
  
• Shade-tolerant at seedling stage
  
• Wide soil tolerance (acid, neutral, swamp, volcanic)
  
• Produces abundant viable seeds (200,000–425,000 seeds/kg)
  
• Wind- and water-dispersed seeds
  
• Intentionally spread by humans (widely planted for timber and as street tree)
  
• Coppices and produces root suckers (resprouts after cutting or fire)

Low Risk Traits:

• Not toxic to humans or animals
  
• No persistent seed bank (viability < 1 year)
  
• Not bird-dispersed
  
• Lacks spines, thorns, or burrs